. Deep borehole surveys and problems. Boring. 26 DEEP BOREHOLE SURVEYS AND PROBLEMS chain on to the scroll paper winding on a shaft. As soon as the feed apparatus turns backward, , on dropping into the borehole, the paper roll is automatically cut out; the pen then indicates a straight line across, as when the plant is at rest. The pen works by clockwork and in one hour moves over the breadth of the paper and after auto- matic reversal works back in the next hour. Thus the record is a continuous zigzag line. The apparatus is enclosed in a glass-topped case which permits of a constant. Fig.
. Deep borehole surveys and problems. Boring. 26 DEEP BOREHOLE SURVEYS AND PROBLEMS chain on to the scroll paper winding on a shaft. As soon as the feed apparatus turns backward, , on dropping into the borehole, the paper roll is automatically cut out; the pen then indicates a straight line across, as when the plant is at rest. The pen works by clockwork and in one hour moves over the breadth of the paper and after auto- matic reversal works back in the next hour. Thus the record is a continuous zigzag line. The apparatus is enclosed in a glass-topped case which permits of a constant. Fig. 5.—Lapp's stratigraph. observation of the progress of the borehole respecting the corresponding time. It does not cut out when the plant is idle as in the case of Jahr's device, and, since this latter is a check on the actual working time, it can be considered that Jahr's method is superior. But it can be applied to percussive boring since it works off the tool feed; however this may be a source of uncertainty since the feed is here hand operated. Thus the record depends on the careful manipulation of the feed which if correct, , if the record corresponds exactly to the progress of the hole, will give uniform results with Jahr's method. Both methods lack in that uniform rotation of the rods is not always obtained in practice. The Foraky Recorder.—This stratigraph is a clockwork device with paper roll and recording apparatus. The. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Haddock, M. H. (Marshall Henry). New York, McGraw-Hill
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Keywords: ., bookcentury1900, bookcollectionb, bookpublishernewyorkmcgrawhill
